How do they come up with the estimated number of asteroids larger than 1 km? Is it based simply on sampling a volume of observed space and extrapolating? Or do they have some way of inferring based on gravitational effects and anomalies?
> Is it based simply on sampling a volume of observed space and extrapolating
Yes, that's pretty much it. It's not as bad as perhaps it sounds. The age of the solar system means that the asteroid belt is mostly stable, which means the distribution can be inferred.
The Kuiper belt and Oort cloud may throw some outliers in occasionally, though. We don't know enough about them yet.
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How do they come up with the estimated number of asteroids larger than 1 km? Is it based simply on sampling a volume of observed space and extrapolating? Or do they have some way of inferring based on gravitational effects and anomalies?
> Is it based simply on sampling a volume of observed space and extrapolating
Yes, that's pretty much it. It's not as bad as perhaps it sounds. The age of the solar system means that the asteroid belt is mostly stable, which means the distribution can be inferred.
The Kuiper belt and Oort cloud may throw some outliers in occasionally, though. We don't know enough about them yet.